Exteriors were shot on location in Lanzarote in the Canary Islands. The location was chosen after Cumming promoted it with photos from her holiday. Grimwade decided to use the island for multiple settings and the island's volcanic landscape also doubled for the planetSarn. Grimwade had trouble writing for the setting, having never been there. John Nathan-Turner denied his request to accompany the select members of the crew to the island. (INFO: Planet of Fire)

Planet of Fire also had a notable guest cast: Peter Wyngarde had starred as flamboyant amateur detective Jason King in Department S and Jason King, while Barbara Shelley had appeared in various Hammer horror films.

Contents

The Master re-establishes psychic control of his robot slave Kamelion. He wants to hijack the Doctor's TARDIS to reach the planet Sarn, where he seeks the healing power of Numismaton Gas to restore himself. Once on Sarn, Turlough comes face to face with his destiny and his death.

On the desolate volcanic planet Sarn, chief elder Timanov counsels the young Chosen One Malkon on how to act in the wake of increased seismic activity, heralding the imminent volcanic catastrophe known as the Time of Fire. Their god Logar, the devout Timanov warns, is greatly displeased at the number of unbelievers. As the Chosen One – so chosen due to the triangular "Mark of Logar" on his arm – Malkon has sole authority to assign heretics to burn in the Cave of Fire and thereby appease their god. Malkon doubts his resolve to condemn unbelievers to death. Meanwhile, two such unbelievers, Amyand and Roskal, scale the forbidden Mountain of Fire – believed to be Logar's dwelling place – and find the crater at the top empty. Now fully convinced that Logar is a myth, they return to the village to spread the news.

As the Fifth Doctor muses bitterly about Daleks and the departure of Tegan, Kamelion's agonised cries are heard from an adjoining room. He has linked himself to the TARDIS data core. The TARDIS then picks up a distress signal; Turlough recognises the pattern and is sufficiently dismayed that he disables the communicator to stop the signal. The TARDIS coordinates have been changed, apparently by Kamelion, and they are en route to the source of the signal, the island of Lanzarote.

American archaeologist Howard Foster and his team are trolling the nearby seabed for ancient relics. Among the artefacts they pull up is a strange, anachronistic metal object also bearing the Mark of Logar. Howard's restless stepdaughter Peri Brown, accompanying the expedition while on holiday from university, is bored and wants to travel with her friends to Morocco. Howard appears to relent but strands her on the boat to make her miss her flight. Peri is furious at Howard but finds his wallet full of money and an alien object Howard had fished out of the lake. She thinks it may be worth some money. Peri strips to her bikini and stuffs the artefact, Howard's money and her clothes into a plastic bag. She then jumps in the sea and begins swimming to shore.

The Doctor's currency of unknown origin.

While the Doctor explores the island trying to find the source of the signal, Turlough has returned to the TARDIS, where he finds Kamelion at the console trying to establish contact with an unknown entity. Turlough overloads the console to disable him out of anger, thinking the signal may be from Trion. On the monitor, he sees Peri struggling in the water and beginning to drown. He runs out of the TARDIS, strips to his bathing suit, jumps into the water and swims out to her. He pulls her ashore and takes her to Tegan's old room to recuperate. He finds the alien artefact in the bag, pulling up his sleeve to show that he too bears the Mark of Logar on his arm. While Peri tosses and turns, muttering incoherent apologies, Kamelion seizes on her psychic impulses and transforms into Howard. The Doctor has traced the signal back to the artefact now in the TARDIS. The doors close and the TARDIS takes off automatically, apparently returning the object to its planet of origin, Sarn. Kamelion enters as Howard, but his mannerisms are like someone else's. After putting her clothes back on over her swimsuit, Peri enters the control room, confused as to where she is.

In the great hall on Sarn, Timanov and Malkon attempt to quell the citizens' unrest due to the impending Time of Fire. The arrival of Amyand and Roskal with the news of their findings causes even more disruption. A desperate Timanov calls for a sign from Logar, and a burst of flame from the Cave of Fire is the apparent answer. Timanov seizes this as a call from Logar to burn the unbelievers. Just then, a lookout announces the arrival of the TARDIS, describing it in a way that corresponds with their legend of the Outsider, a representative of Logar. Timanov urges Malkon to condemn the heretics, but he hesitates.

Once the Doctor and Turlough leave to explore, "Howard" announces that contact has been established and that he now has control of the TARDIS. As he laughs maniacally, his features change into that of the Master before Peri's horrified eyes.

The Doctor and Turlough explore the apparently deserted village square finding the triangular pattern, which Turlough identifies as the Misos Triangle, etched on a column. The Misos Triangle is an emblem of Turlough's home planet, Trion, but he is not forthcoming with further details. They do not notice another TARDIS materialising nearby.

The Master's control of Kamelion is tenuous, and the shape-shifting robot momentarily regains self-control. He removes the TARDIS's comparator and urges Peri to give it to the Doctor, but then loses his self-will and his form shifts back to the Master. He pulls her out into the village square towards the Master's TARDIS, but a sudden tremor knocks it over, door-side down and a large rock falls hitting Kamelion causing him to fall over which allows Peri to escape into the desolate wilderness. The Master, trapped inside his TARDIS, orders Kamelion to pilot the Doctor's TARDIS inside his own, but without the comparator it won't function.

Turlough reveals his Misos Triangle to Malkon.

The unbelievers storm the great hall, having found and befriended the Doctor and Turlough, displaying the travellers as the Outsiders. Turlough discovers the Misos Triangle on Malkon's arm, showing his own. He is convinced that the relics in the hall are from his father's ship and that Malkon might be his younger brother. Malkon describes how he was found in the Place of Fire as an infant, and Turlough convinces him to take him there, where they find the wreckage of a crashed spaceship. They encounter Peri, who had been wandering lost since eluding "the Master". When Turlough learns that the Master is involved, they dash back to the village to warn the Doctor.

The Doctor, however, finds himself at the mercy of Timanov and his own Outsider, the Kamelion/Master. Under the "Master's" sway, Timanov orders the sacrifice of the unbelievers to the flame. "The Master" demands the return of the comparator, which the Doctor doesn't have, as his new allies are pushed toward the mouth of the Cave of Fire.

Malkon demands that the execution cease, but is shot down in the ensuing struggle. Timanov has the unbelievers and the Doctor locked into the cave with the flame. Turlough uses a Trion relic to remotely disable the sacrificial flame, which Timanov shows as a sign of displeasure from Logar at Malkon's apparent assassination. Still fooled by the "Master", Timanov leads a team of Sarns in helping to shift the Master's TARDIS, but once upright, "the Master" pulls Peri inside and dematerialises. Turlough arrives and releases the Doctor and the unbelievers from the cave.

The Doctor struggles to figure out why the Master is on Sarn, and how to rescue the citizens from the impending doom of the volcanic eruption. He also reasons that the Trions had a more productive use for the Cave of Fire than mere sacrifice. Timanov speaks of a time when he was young, and he encountered Logar who took him to a bath of blue flame that rejuvenated him.

The Master's TARDIS materialises in a control room deep below the volcano. "The Master" enlists Peri's assistance, on pain of death from his Tissue Compression Eliminator weapon, in controlling the machinery there to harness the power of Numismaton Gas, which is indeed a bright blue flame renowned for its healing properties. The Doctor takes advantage of the presence of the Numismaton flame to heal the ailing Malkon in the Cave of Fire. Eluding the Kamelion/Master and ducking into the Master's TARDIS, Peri locates what she reasons must be Kamelion's control box. Lifting the lid, she finds the Master lurking within, reduced to mere inches in height.

The Master, having accidentally shrunk himself while attempting to upgrade his TCE weapon, seeks the power of the Numismaton Gas to restore himself. He constructed the control box to re-establish contact with his slave Kamelion to help him reach Sarn.

Peri accidentally knocks the Master's control box over which allows the Master to escape into his TARDIS. Peri tries to track him down and swat him with her shoe, but he escapes and hides in the TARDIS console. There, he taunts Peri and shorts the controls to open the TARDIS door. Peri runs out and into the wilderness

The Doctor and Amyand, with Peri's help, have reached the Numismaton gas control room. They find protective metallic suits which correspond with the traditional image of Logar. The Doctor realises that the Trions have used the control room to regulate the seismic activity, but the impending eruption will be too big to control. The Doctor sends Amyand back to the ruins wearing the only remaining suit. Kamelion pilots the Master's TARDIS into the blue flame and brings out the control box, bearing the Master within. As Kamelion advances menacingly on the Doctor with the TCE, he overloads the gas control circuitry to give Kamelion a near-fatal "heart attack." Kamelion, now freed from the Master's control, begs for destruction, and the Doctor complies with the TCE.

The Master is restored to full height by the Numismaton gas and gleefully describes the tortures that await the Doctor at his hands. But the Doctor's fiddling with the controls cuts off the gas, leaving the Master to burn in the full power of the naked flames. The Master's pleas for mercy go unheeded and the Doctor watches as his enemy is apparently consumed by fire.

Turlough bids the Doctor goodbye.

Turlough, despite his status as a Trion political prisoner, swallows his pride and manages to re-activate the communication system in the wreckage of his father's ship, summoning a Trion rescue ship to pick up the Sarn survivors. Timanov, humbled by his easy manipulation by the Master in the name of his god, declines rescue and opts to perish in the ensuing volcano. Acting on instructions from the Doctor, Turlough programs the TARDIS to rescue the Doctor and Peri from the gas control room before it is destroyed. The Trion captainLomand informs Turlough that due to a general amnesty, his exile has been lifted and he is free to return home. Turlough thanks the Doctor, who understands Turlough's reasons for wanting to return to Trion, for everything and the two warmly bid each other farewell. Peri, on the other hand, asks to travel with the Doctor for the remaining three months of her vacation. The Doctor agrees, and he welcomes her aboard the TARDIS as it takes flight.

The Fifth Doctor adapts his outfit for the hot weather in Lanzarote. His coat and cricket jumper are left behind in the TARDIS, and he wears a beige coloured waistcoat with a gold, white and red flower and plant pattern. Before departing Lanzarote for the planet Sarn, the Doctor discarded the waistcoat but did not put back on his coat and jumper.

Vislor Turlough's rank is Junior Ensign Commander. He is from Trion and he was on the losing side in the planet's civil war.

Turlough's father and his brother Malkon were exiled to Sarn, where the Trions sent occasional prisoners. Such prisoners were branded with the Misos Triangle and the indigenous population heralded them as leaders chosen by Logar, their fire god. Turlough's father died when the spacecraft crashed. The volcanic forces of Sarn were kept in check for a while by Trion scientists.

The Master controls Kamelion, forcing him to control the TARDIS. The Master tries to use hypnosis through Kamelion, on Peri, in vain, partly because she has a "strong" will.

The Master claims he is superior to the Doctor in the same line as his TARDIS is superior to the Doctor's.

According to Turlough, the Trions have undercover agents on every civilised planet, and cites as possible examples an agrarian commissioner on Verdon, a tax inspector on Darvey, and a very eccentric solicitor in Chancery Lane.

Turlough defines the Brendon School as the "worst place in the universe".

Kamelion appears for the first time since The King's Demons the previous season; complications involving the robot model prevented him from appearing in other episodes, although a scene was filmed for The Awakening but cut before transmission. Kamelion's "death" makes him the fourth known companion to die while travelling with the Doctor, following Katarina, Sara Kingdom, and Adric.

It was during the production of this serial that Peter Davison and Nicola Bryant participated in their infamous "James Bond" photo shoot, in which Davison donned a tuxedo and prop gun and Bryant a bikini.

This is the only televised Fifth Doctor story not to visually contain Tegan Jovanka. The Doctor's reference to Tegan at the beginning of part one means that she was technically a part of every single one of his television stories in some way. To date, the only other companion to have been a part of every televised story of a given Doctor is Rose Tyler, who appeared in every episode during the Ninth Doctor era.

Radio Times incorrectly credits Nicola Bryant as "Perpugillian Brown" and Gerald Flood as "Voice of Kamelior".

The Master's final line before apparently being killed is directed squarely at the Doctor: "Won't you show mercy to your own ..." According to the DVD commentary, Fiona Cumming asked John Nathan-Turner how the line was to end, to which he replied, "brother". However, Anthony Ainley never said the word in any take captured on video. Thus fans were free to speculate about how the line was to have ended. In TV: The Sound of Drums, the Tenth Doctor strongly implies that the Master was not his brother.

The studio and location shots of Turlough rescuing Peri don't quite match up. She's still wet from her near-drowning when Turlough gets her to the exterior of the TARDIS doors, but is dry when they cut to the interior, studio shot.

This really isn't Peri's passport at all, but one belonging to a man named Sydney who was born in New York in 1940

According to directorFiona Cumming in the DVD commentary, Peri's passport was not specifically made for this production, but was, rather, the reuse of a passport that actor Dallas Adams had used in another production. Therefore, any details gleaned from freeze-framing the close-ups on the prop — such as her birth date and location — were not specific to Peri, but to the character Adams had played in the other production. Thus, they are technically production errors. Oddly, the production subtitles on the DVD champion the information contained within the passport, despite Cumming's revelations about the true origin of the prop.

In PROSE: Shell Shock, it is strongly implied that Howard sexually abused Peri when she was younger. Some read this as supporting Peri's dream-state behaviour in this story where she shouts out Howard's name after saying, "Don't turn out the light." However, by concentrating on just these two lines, the two previous lines —"No, Howard. Please don't leave me alone." — are conveniently ignored. It's somewhat unlikely that a person plagued by parental abuse would be begging for the abuser to stay with her. Indeed, the DVD commentary makes it very clear the production team were aiming for a positive, friendly relationship between the two characters and there's not much more than Shell Shock which suggests anything improper between Howard and Peri. In fact, AUDIO: The Reaping details the reasons for the divorce of Howard and Peri's mother Janine Foster and completely fails to mention any sort of sexual abuse. Shell Shock is thus one view of the relationship between Peri and Howard, which has never been supported clearly by any performed Doctor Who.

This story was first released on DVD in the UK on 14 June2010 as part of the Kamelion Tales box set. The two-disc set includes a restored version of the story, as well as the following special features:

Highlight 'The Flames of Sarn' and press left to reveal a hidden Doctor Who logo. Clicking on this gives you a short compilation of the countdown clocks for the story.

On the audio menu on disc one choose Isolated Score making sure that the words are highlighted, then press the right button on your remote and the Doctor Who logo should go green. Selecting this gives you a short piece on facts from the story.

Plus a new Special Edition of Planet of Fire in 16:9 widescreen format, with 5.1 surround sound, CGI effects and extra footage.

Contrary to common belief, season 10 kicked off in the last week of December 1972 — not in 1973, as would be expected. Season 10 actually began nine years after season 1 started. In fact, The Three Doctors began nine years to the week after The Daleks first aired.

For the purposes of this list, "Series 4" is considered to be the production series 4, which ran all the way from Time Crash to The End of Time.

The years seen in this section may seem decidedly "off". Remember, however, that this list only gives the first year in which an episode from a series was broadcast. David Tennant, unusual amongst other Doctors, began and ended on special episodes, not regular ones. Thus, his series actually begin in 2005, 2006 and 2007 — not 2006, 2007 and 2008 as is commonly thought.